我怎样才能强制自动生成的hibernate主键 [英] How can I force positive auto generated hibernate primary keys

问题描述

我使用的是Hibernate 4.3.8的JPA 2.1。在Oracle，MySQL，PostgreSQL和MS SQL上。为了创建数字主键，我使用了以下代码：

  @Id 
 @Column（name =ID ）
 @GeneratedValue（strategy = GenerationType.AUTO，generator =t_gen）
 @SequenceGenerator（name =t_gen，sequenceName =T_SEQ）
 private long id; 
  

到目前为止这么好。但是我需要在所有条件下仅生成ID的正值。如何强制Hibernate在每个数据库（MS SQL，MySQL，PostgreSQL，Oracle）上只生成正面的ID？解析方案

这有助于;

如果未在实体端声明allocationSize，则默认分配大小为50个所有序列必须在DB端声明INCREMENT BY 50。

参考链接：
http://skay-dev.blogspot.in/2013/09/hibernate-sequence-and-negative.html

I am using JPA 2.1 with Hibernate 4.3.8. on Oracle, MySQL, PostgreSQL and MS SQL. For creating numeric primary keys I have used the following code :

  @Id
  @Column(name = "ID")
  @GeneratedValue(strategy = GenerationType.AUTO, generator = "t_gen")
  @SequenceGenerator(name = "t_gen", sequenceName = "T_SEQ")
  private long id;

So far so good. But I need to generate only positive values of IDs under all conditions. How can I force Hibernate to generate only positive ID's on each database (MS SQL, MySQL, PostgreSQL, Oracle) ?

解决方案

Hope this helps;

If allocationSize is not declared on the entity side, as default allocation size is 50 ALL sequences MUST declare INCREMENT BY 50 on the DB side.

Reference Link: http://skay-dev.blogspot.in/2013/09/hibernate-sequence-and-negative.html

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